Wire printer with print head moved in figure eight pattern

ABSTRACT

A printer for generating a dot matrix has a single print element that sweeps out a dot matrix for a character position, row by row with respect to a continuously moving document. A single print head which is motion synchronized with the document guides a series of such print elements through a closed curved path to sweep out the matrix as a series of rows of dots at each character position. Interrelating the adjoining character positions to generate a continuous matrix of dot positions also enables the printer to be used to print graphics or as an XY plotter.

United States Patent [1 1 Knappe WIRE PRINTER WITH PRINT HEAD MOVED IN FIGURE EIGHT PATTERN [75] Inventor: Laverne Frank Knappe, Rochester,

Minn.

[73} Assignee: International Business Machines Corporation, Armonk, NY.

221 Filed: Mar. 31, 1972 211 App1.No.:240,113

[52] US. Cl. 101/93 C, 197/1 R v [51] Int. Cl. B41] 3/12 [58] Field of Search 101/93 C; 197/1; 178/6.6, 23, 30

[56] References Cited UNITED STATES PATENTS 3,167,166 1/1965 Schiebeler 197/l R 2,938,455 5/1960 Jurgens et al.... 101/93 C 3,302,557 2/1967 Simpson 197/1 R X 2,728,289 12/1955 Johnson et a1. 197/1 R X 3,333,667 8/1967 Nordin 197/1 R [45] July 3, 1973 Primary Examiner-Robert E. Pulfrey Assistant Examiner-E. M. Coven Attorney-Robert W. Lahtinen et a1.

[5 7] ABSTRACT A printer for generating a dot matrix has a single print element that sweeps out a dot matrix for a character position, row by row with respect to a continuously moving document. A single print head which is motion synchronized with the document guides a series of such print elements through a closed curved path to sweep out the matrix as a series of rows of dots at each character position. lnterrelating the adjoining character positions to generate a continuous matrix of dot positions also enables the printer to be used to print graphics or as an XY plotter.

11 Claims, 5 Drawing Figures PMENIEDJUL3 um mm: or '4 FIG. 3

WIRE PRINTER WITH PRINT HEAD MOVED IN FIGURE EIGHT PATTERN FIELD OF THE INVENTION This invention relates to printers and more particularly to a printer which generates a matrix of printed indicia that may be selectively actuated to generate characters, plots or graphics.

BACKGROUND OF THE INVENTION Wire printers are commonly used wherein a plurality of styli or wire print members are axially moveable to provide an impact printing function. By providing actuation of selected elements of the matrix at each print position, characters may be formed. By forming a continuous uniform matrix of dot print positions, such a device may be used as an XY plotter or for the presentation of pictorial or graphic information. If the printeris used to print a single line of characters, a single matrix may be used with the document indexed from character position to character position with respect to the print head. If a X 7 matrix is used, 35 wires and a like number of independent actuating assemblies are required for a single character position. Accordingly, as the number of matrices are proliferated to afford multiple print positions, either the associated mechanism becomes bulky and complex or the use of a single matrix will result in slow execution of the print function and often more complex document indexing past the print head.

One way in which the multiplicity of print elements is reduced is through the use of a singlerow of wire print elements that generate the matrix a row at a time. If a complete row of print elements is provided across the document at a direction transverse to document travel, the document motion may be in a single direction while permitting complete printing of the docu ment to the full print width. Similarly a series of print wires aligned in a single column may be used to print a continuous line of characters across a document.

In the printer of the present invention,'each character is generated by a single print wire element that processes through a closed path to provide two horizontal rows of dot positions on a continuously moving document during each cycle. The path swept by the print wire terminal end adjacent the document is substantially in the form of a figure 8 rotated 90. The intersecting portions of the path are linear with the progression of the print wire terminal end in the direction of document travel being at the same velocity as the docu ment causing a series of printed dots to be two horizontal lines during each complete cycle of travel. A single print head carries a wire terminal end portion at each character position and consequently a single cam drive system with a single emitter coordinating mechanism synchronizes each of the print positions of each wire print element with the issuance of print commands from a control unit.

Further, by having adjacent character position print wires positioned to generate cooperating horizontal and vertically positioned dot matrices; a continuous, uniformly spaced matrix of dots can be formed on the document in both longitudinal and transverse directions. This not only enables the printer to function to generate printed characters, but also as an XY plotter or facsimile recorder to generate graphic or pictorial information. In this mode, operating as an XY plotter information from a computer is stored in buffer storage and processed to generate the graph or picture at a constant document speed. It would also be possible to program the device to print in both forward and reverse directions of document motion under machine logic control.

It is an object of this invention to provide a wire printer which uses a single print wire element to sweep out a complete rnulti-line dot matrix such as a character position. It is a further object to provide a unitary drive structure for simultaneously driving a single print element at each of a series of print positions to sweep out a matrix of print positions. It is also an object to provide such a matrix printing device which provides a continuous dot matrix across the full printed width of a document to facilitate use as a plotter or for generating graphics.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation of a wire printer incorporating the invention with portions shown in phantom view and selected parts removed.

FIG. 2 is a plan view of the printer of FIG. 1 partially broken away and with portions removed.

FIG. 3 is a right side elevation of the printer of FIG. 1 partially broken away and with structural portions removed to more clearly show the print wire actuating mechanisms and ink transfer means.

FIG. 4 is a left side elevation of the printer of FIG. 1 with portions broken away.

FIG. 5 is a schematic showing of the path swept by a single wire print element with differing vertical and horizontal scales for purposes of illustration.

DESCRIPTION Referring to FIG. 1, a motor 20 is connected to a dual timing belt pulley 21 on an output shaft 22 which drives timing belt 24 associated with a sprocket drive for moving a continuous form document 25 and a timing belt 27 which provides power for driving a print head 30 through a continuous closed curve path coordinated with the advance of document 25.

As seen in FIG. 4, ashaft 31 has a pulley 32 rigidly secured thereto at one end and a worm gear 33 secured to the opposite end to affect rotation in unison with such shaft. A shaft 35 carries a pair of sprockets 36 that engage the perforate margins of document 25 and is driven by a spur gear 37 rigidly secured thereto which engagesone gear 33. Accordingly, timing belt 24 drives pulley 32 at a reduced speed with respect to the motor output shaft 22 and the drive connection between worm gear 33 and spur gear 37 further reduces the speed at which sprocket 36 moves the continuous form document over a print platen 39 and along a guide plate 40.

Timing belt 27 drives a dual pulley 41 secured to shaft 42. Also secured to shaft 42' for rotation in unison therewith is a cam 43 (FIG. 2) that engages the end surface 44 of print head 30 to induce horizontal reciprocation thereof during cam rotation. Print head 30 is maintained in contact with cam 43 by a spring element 46 that biases print head 30 toward the cam surface. Dual pulley 41 secured to shaft 42 also engages belt 47 to drive pulleys 48 and 49 while being trained around an idler 50. Timing belt pulleys 41, 48 and 49 are all the same diameter causing the respectively associated shafts 42, 51 and 52 to rotate in unison at a common rotational speed. As seen in FIG. 2, shaft 51 also carries a cam 53 which engages the lower surface 54 of print head 30 while shaft 52 carries a cam 55 which engages a transversely spaced lower print head surface 56. Cams 53 and 55 are identical and secured to the respective shafts to simultaneously induce rise and fall of print head 30. A tension spring 57 is connected at the upper end to print head 30 and at the lower end is connected to a projection 62 which forms a part of the machine frame and functions to maintain continuous contact between earns 53 and 55 and the respectively associated print head follower surfaces 54 and 56.

Shaft 42 also carries for rotation in unison therewith, an 18 tooth emitter wheel 58 and a single tooth emitter wheel 59, the function of which will be defined hereafter. A variable reluctance emitter pickup 60 cooperates with emitter wheel 58 while emitter pickup 61 is aligned to cooperate with emitter wheel 59.

As seen in FIG. 1 and FIG. 3, a series of print wires 63 each extend through print tubes 64 to respective character positions 65 along print head 30. Each print wire is actuated by an electromechanical actuator assembly 66. The actuator assemblies 66 are mounted in a confronting double row with the actuating armature 67 interdigitated to present the actuating connections with the respective print wire 63 along a common line. Each actuator assembly 66 includes a coil 68, about a core 69, which is selectively energized to attract the associated armature 67. Upon actuation, armature 67 drives the associated print wire 63 axially through tube 64 causing the opposite axial end of the print wire which normally terminates within the print head 30 to be driven toward platen 39 to print a dot on document 25 by transfer from an ink source such as the carbon ribbon 70.

The movement of cam 43 to displace the print head 30 horizontally and earns 53 and 55 to vertically displace print head 30 are interrelated to cause each print wire position 65 at the print head 30 to process through a figure 8 path as shown in FIG. 5 The motion of the print wire 63 as shown in FIG. 5 has been illustrated with different horizontal and vertical displacement scales for purposes of clearer illustration.

As seen, there are 18 positions shown in the figure 8 path of travel illustrated in FIG. 5. Positions 1-8 and 10-17 are along linear paths. These positions are representative of the path taken in the direction of arrows A by the axial end portion of a print wire 63 as confined by print head 30. The document motion which is also coordinated with the motion of the print wire is in the direction of arrow B. Between adjoining counts or print wire positions l-8 the document advance is equivalent to the vertical component of print wire travel between position 1 and position 2. Accordingly, if print commands are executed by actuating print wire armature 67 at each of positions l8, the eight printed dots would lie on a single horizontal line on the document 25. Between position 8 and position 10, the print wire is moved through a path with a vertical component. Between positions 10 and 17, the print wire sweeps along a linear path and once more may print a horizontal line of dots respectively underlying positions 1-8, but printed in the opposite horizontal direction. The periods between positions 8 and 10 and also between positions 17 and 1 are used to position the print wire for the next row of dots and accordingly positions 9 and 18 are not utilized as print positions. The horizontal projection between any two positions in the linear sequences 1-8 and 10-17 is equivalent to the vertical pitch between adjacent horizontal rows. Consequently, as the print wire is moved through the closed path as shown, the print positions generate a continuous, uniformly spaced matrix of dots, eight positions wide with respect to the document. When printing only characters it may be neither necessary nor desirable to generate a uniform matrix and accordingly the horizontal pitch between dots may be different from the vertical pitch between rows.

Also, the paths of the axial ends of adjoining print wires 63 overlap to cause a dot printed at position eight of a print wire and a dot printed at position one of the print wire immediately to the right thereof as viewed in FIG. 1 to be a common line with the same horizontal pitch as adjoining dots printed within the sweep generated by either of the print wires. Accordingly, the series of print head wire positions cooperate to enable the printing of a continuous matrix of dot positions across the full printing width of the print head 30 and continuously along the document 25. In this mode, the printer can function as an XY plotter or facsimile recorder to print graphic or pictorial information as well as characters.

To print characters, each print wire 63 can be used to sweep out one character position at each print line location. A 6 X 8 or 5 X 7 character matrix may be used to provide selectively two or three dot positions of horizontal spacing between characters. Likewise, horizontal print lines may be blank to provide vertical spacing between adjoining lines of characters.

In operation the document drive is synchronized with the motion of print head 30 to provide that during the printing or the progress of the print elements past a sequence of horizontal print positions, the component of print head velocity in the direction of document motion is equivalent to the velocity of the document. Thus, as cams 53 and 55 rise, the velocity imparted to print head 30, in the direction of document motion, is such that the vertical component of print head motion is in unison with document motion. Cam 43 has rising and falling surfaces which are synchronized with the rotation of earns 53 and 55 to impart the motion illustrated in FIG. 5 to each print head position 65. The linear progressions beginning at positions 1 and 10 and extending through positions 8 and 17 respectively, function to sweep out two horizontal rows of print positions as the print head processes through each cycle of motion. To provide a uniform matrix of print positions the transverse velocity imparted by cam 43 intermediate print positions in a given row sequence is nine times the document velocity in the device of the illustrated embodiment.

The emitter wheels 58 and 59 which also are synchronized with the motion of document 25 and print head 30 identify the print positions to permit coordinating of the print commands in accordance with the data characters, plots or graphics that are to be generated on the document 25. The single tooth emitter wheel 59 provides the initializing signal through pickup 61 for each cycle of motion of print head 30 while emitter wheel 58 through pickup 60 generates the count identifying the print positions.

It will be appreciated that although the illustrated embodiment shows the control of a wire print element for impacting printing, the invention could likewise be applied to other printers that generate characters and other data by generating a matrix of dots or marks. For example the same result could be achieved by guiding a series of ink droplet emitting nozzles in the environment of an ink jet printer where printing occurs by control of the nozzle position rather than by droplet deflection induced by a field potential. Accordingly, while the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. Apparatus for forming a character on a moving document comprising a longitudinally moveable stylus element;

support means for supporting the terminal end of said stylus element adjacent said document and confining said stylus element in directions perpendicular to the direction of longitudinal motion;

document moving means for imparting motion to said document;

drive means for moving said support means through a continuous closed path including two intersecting sequences of print positions, during each of which said support means moves in unison with said document in the direction of document travel and relative to said document in a direction traverse to the direction of document travel;

selectively operable means for driving said stylus element toward said document;

means for imparting an image on said document upon actuation of said selectively operable means; and

interconnecting means connected to said drive means and to said document moving means to interrelate motion of said support means and motion of said document.

2. The apparatus of claim 1 wherein said stylus element is a wire print element and said selectively operable means is an electro magnetic means including an electro magnet and armature connected to said wire print element to impart an axial motion thereto upon actuation of said electro magnet.

33. The apparatus of claim 2 wherein said means for imparting an image comprises an ink transfer means interposed between the print surface of said stylus element and said document.

4. The apparatus of claim 1 wherein said support means comprises a print head for guiding the terminal portion of said stylus element in a plane generally perpendicular to the axis of said stylus element at said print head, said stylus element being moveable axially with respect to said print head under control of said selectively operable means.

5. The apparatus of claim 4 further comprising means for identifying said sequence of print positions along said closed path and wherein said drive means comprises first cam means for imparting a first motion component to said print head and a second cam means for imaprting a second motion component to said print head and means interrelating the motion of said first cam means and said second cam means, said second cam means imparting a motion component in the direction of document travel with a velocity equivalent to the document velocity at each of said sequence of print positions.

6. A printer for printing data on a moving document using selected dots from a matrix pattern comprising a moveable print head adjacent said document;

print means having a print element guided by said print head for printing a dot on said document upon actuation thereof;

first drive means for moving said print head through a continuous closed path including two intersecting sequences of print positions, during each of which said print head moves in unison with said document in the direction of document travel and relative to said document in a direction traverse to the direction of document travel;

second drive means for moving said document; and

interconnecting means connecting said first and second drive means, said first and second drive means being interconnected to synchronize the movement of said print head with motion of said document.

7. The printer of claim 6 wherein said print means comprises a series of wire print assemblies having the print elements thereof in spaced positions along siad print head and disposed in a direction generally perpendicular to the direction of document travel and wherein each said print wire element is disposed to sweep out a dot matrix for one character position along a document print line.

8. The printer of claim 7 wherein said print elements of said series of wire print assemblies are aligned and guided by said print head to produce uniformly spaced continuous dot matrix print positions across said document print line.

9. The printer of claim 6 wherein said first drive means comprises first cam means having a rise and fall which imparts a motion to said print head in a direction generally perpendicular to the direction of travel to said document and second cam means having a rise and fall which imparts motion to said print head parallel to the direction of document travel.

10. The printer of claim wherein said first and second cam means cooperate to drive said print head through said continuous closed path with said sequence of print positions respectively occurring during two linear portions when said motion imparted by said second cam means is in unison with the motion of said document whereby said print element may be actuated to print two parallel rows of dots in a direction perpendicular to the direction of document travel during each cycle of print head motion.

11. The printer of claim w further comprising an electric motor; and

timing belt means operatively connected to said first and second cam means and said electric motor for synchronizing rotary motion of said motor, said first cam means and said second cam means.

, s a r a t: 

1. Apparatus for forming a character on a moving document comprising a longitudinally moveable stylus element; support means for supporting the terminal end of said stylus element adjacent said document and confining said stylus element in directions perpendicular to the direction of longitudiNal motion; document moving means for imparting motion to said document; drive means for moving said support means through a continuous closed path including two intersecting sequences of print positions, during each of which said support means moves in unison with said document in the direction of document travel and relative to said document in a direction traverse to the direction of document travel; selectively operable means for driving said stylus element toward said document; means for imparting an image on said document upon actuation of said selectively operable means; and interconnecting means connected to said drive means and to said document moving means to interrelate motion of said support means and motion of said document.
 2. The apparatus of claim 1 wherein said stylus element is a wire print element and said selectively operable means is an electro magnetic means including an electro magnet and armature connected to said wire print element to impart an axial motion thereto upon actuation of said electro magnet.
 3. The apparatus of claim 2 wherein said means for imparting an image comprises an ink transfer means interposed between the print surface of said stylus element and said document.
 4. The apparatus of claim 1 wherein said support means comprises a print head for guiding the terminal portion of said stylus element in a plane generally perpendicular to the axis of said stylus element at said print head, said stylus element being moveable axially with respect to said print head under control of said selectively operable means.
 5. The apparatus of claim 4 further comprising means for identifying said sequence of print positions along said closed path and wherein said drive means comprises first cam means for imparting a first motion component to said print head and a second cam means for imaprting a second motion component to said print head and means interrelating the motion of said first cam means and said second cam means, said second cam means imparting a motion component in the direction of document travel with a velocity equivalent to the document velocity at each of said sequence of print positions.
 6. A printer for printing data on a moving document using selected dots from a matrix pattern comprising a moveable print head adjacent said document; print means having a print element guided by said print head for printing a dot on said document upon actuation thereof; first drive means for moving said print head through a continuous closed path including two intersecting sequences of print positions, during each of which said print head moves in unison with said document in the direction of document travel and relative to said document in a direction traverse to the direction of document travel; second drive means for moving said document; and interconnecting means connecting said first and second drive means, said first and second drive means being interconnected to synchronize the movement of said print head with motion of said document.
 7. The printer of claim 6 wherein said print means comprises a series of wire print assemblies having the print elements thereof in spaced positions along siad print head and disposed in a direction generally perpendicular to the direction of document travel and wherein each said print wire element is disposed to sweep out a dot matrix for one character position along a document print line.
 8. The printer of claim 7 wherein said print elements of said series of wire print assemblies are aligned and guided by said print head to produce uniformly spaced continuous dot matrix print positions across said document print line.
 9. The printer of claim 6 wherein said first drive means comprises first cam means having a rise and fall which imparts a motion to said print head in a direction generally perpendicular to the direction of travel to said document and second cam means having a rise and fall which imparts motion to said print head paralLel to the direction of document travel.
 10. The printer of claim 9 wherein said first and second cam means cooperate to drive said print head through said continuous closed path with said sequence of print positions respectively occurring during two linear portions when said motion imparted by said second cam means is in unison with the motion of said document whereby said print element may be actuated to print two parallel rows of dots in a direction perpendicular to the direction of document travel during each cycle of print head motion.
 11. The printer of claim 10 further comprising an electric motor; and timing belt means operatively connected to said first and second cam means and said electric motor for synchronizing rotary motion of said motor, said first cam means and said second cam means. 